Server ubuntu Upgrade

To upgrade from Ubuntu 13.04 server to Ubuntu 13.10 server, do the following steps.
Install the update-manager-core package if it is not already installed:
sudo apt-get install update-manager-core
Edit the file /etc/update-manager/release-upgrades,

[DEFAULT]
# Default prompting behavior, valid options:
#
# never – Never check for a new release.
# normal – Check to see if a new release is available. If more than one new
# release is found, the release upgrader will attempt to upgrade to
# the release that immediately succeeds the currently-running
# release.
# lts – Check to see if a new LTS release is available. The upgrader
# will attempt to upgrade to the first LTS release available after
# the currently-running one. Note that this option should not be
# used if the currently-running release is not itself an LTS
# release, since in that case the upgrader won’t be able to
# determine if a newer release is available.
Prompt=normal
Now it is time to upgrade your server system to latest version using the following command: